Turbocharger

ABSTRACT

A turbocharger includes: a bearing housing (housing); a bearing disposed in the housing and having a thrust bearing surface; and a partition wall portion assembled to the housing, the partition wall portion including an inclined surface positioned on an outer side in a radial direction of the thrust bearing surface, extending at least vertically above the thrust bearing surface, and inclined with respect to a direction perpendicular to the axial direction of a shaft.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/JP2017/013032, filed on Mar. 29, 2017, which claims priority to Japanese Patent Application No. 2016-070560, filed on Mar. 31, 2016, the entire contents of which are incorporated by reference herein.

BACKGROUND ART Technical Field

The present disclosure relates to a turbocharger including a bearing having a thrust bearing surface.

Related Art

In the related art, turbochargers in which a shaft is pivotally supported by a bearing housing in a freely rotatable manner are known. One end of the shaft is provided with a turbine impeller. The other end of the shaft is provided with a compressor impeller. Such a turbocharger is connected to an engine. The turbine impeller rotates by exhaust gas discharged from the engine. The rotation of the turbine impeller causes the compressor impeller to rotate via the shaft. In this manner, the turbocharger compresses the air along with the rotation of the compressor impeller and delivers the air to the engine.

In the turbocharger, a bearing formed with a thrust bearing surface is mounted. The thrust bearing surface receives a thrust load acting on the shaft. For example, in a semi-floating bearing described in Patent Literature 1, an end surface forms a thrust bearing surface. The thrust bearing surface receives a thrust load from an oil thrower member provided in a shaft. In Patent Literature 1, a partition wall portion (lid member) is provided on an outer side in the radial direction of the oil thrower member. The partition wall portion divides a space from the thrust bearing surface to a compressor impeller. The partition wall portion prevents lubricating oil scattered from the thrust bearing surface from flowing toward the compressor impeller side.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No. JP 2015-048755

SUMMARY Technical Problem

Lubricating oil having lubricated a bearing is discharged from an oil discharge port. The oil discharge port is provided below a partition wall portion. However, if the amount of lubricating oil is excessively increased, an oil level of the lubricating oil before being discharged from the oil discharge port rises below the partition wall portion. For this reason, development of a technology for improving the oil draining property is desired.

It is an object of the present disclosure to provide a turbocharger capable of improving the oil draining property.

Solution to Problem

In order to solve the above problem, a turbocharger according to one aspect of the present disclosure includes: a housing; a bearing disposed in the housing and having a thrust bearing surface; and a partition wall portion assembled to the housing, the partition wall portion including an inclined surface positioned on an outer side in a radial direction of the thrust bearing surface, extending at least vertically above the thrust bearing surface, and inclined with respect to a direction perpendicular to the axial direction of a shaft.

The inclined surface may be inclined in such a direction as to extend radially outward toward the bearing.

A groove formed in the housing and facing the inclined surface in the axial direction of the shaft may be further provided.

An oil discharge port formed in the housing and positioned on an imaginary extension line in contact with an outer diameter end portion of the inclined surface positioned vertically below the shaft may be further provided.

An outer diameter wall portion extending outward in the radial direction from the inclined surface in the partition wall portion and a first cutout portion formed on a vertically lower side lower than a center of the shaft in the outer diameter wall portion.

A seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing may be further provided.

The partition wall portion and the seal plate portion may be integrally formed.

A middle portion provided between the partition wall portion and the seal plate portion and a second cutout portion formed in the middle portion in a vertically lower side thereof lower than the center of the shaft may be further provided.

Effects of Disclosure

According to the present disclosure, it is possible to improve the oil draining property.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of a turbocharger.

FIG. 2 is a view of a one-dot chain line part extracted from FIG. 1.

FIG. 3 is a view of a broken line part extracted from FIG. 1.

FIG. 4A is a perspective view of a seal partition member. FIG. 4B is a perspective view of the seal partition member when viewed from a direction different from that of FIG. 4A.

FIG. 5 is a partially extracted view of a bearing housing.

FIG. 6A is a view of the bearing housing when viewed from the right side in FIG. 5. FIG. 6B is a perspective view of a broken line part of FIG. 6A when viewed from below.

FIG. 7 is an explanatory diagram for explaining a modification.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Dimensions, materials, other specific numerical values, and the like illustrated in such embodiments are merely examples for facilitating understanding of the disclosure, and the present disclosure is not limited thereby except for a case where it is specifically mentioned. Note that, in the present specification and the drawings, elements having substantially the same function and structure are denoted by the same symbol, and redundant explanations are omitted. Components not directly related to the present disclosure are not illustrated.

FIG. 1 is a schematic cross-sectional view of a turbocharger C. Hereinafter, descriptions are given assuming that a direction of an arrow L illustrated in FIG. 1 is the left side of the turbocharger C. Descriptions are given assuming that a direction of an arrow R illustrated in FIG. 1 is the right side of the turbocharger C. As illustrated in FIG. 1, the turbocharger C includes a turbocharger main body 1. The turbocharger main body 1 includes a bearing housing 2 (housing). A turbine housing 4 is connected to the left side of the bearing housing 2 by a fastening mechanism 3. A compressor housing 6 is connected to the right side of the bearing housing 2 by a fastening bolt 5. The bearing housing 2, the turbine housing 4, and the compressor housing 6 are integrated.

A protrusion 2 a is provided on the outer circumferential surface of the bearing housing 2. The protrusion 2 a is provided in the vicinity of the turbine housing 4. The protrusion 2 a protrudes in a radial direction of the bearing housing 2. Moreover, a protrusion 4 a is provided on the outer circumferential surface of the turbine housing 4. The protrusion 4 a is provided in the vicinity of the bearing housing 2. The protrusion 4 a protrudes in a radial direction of the turbine housing 4. The bearing housing 2 and the turbine housing 4 are fixed to each other by fastening the protrusions 2 a and 4 a by the fastening mechanism 3. The fastening mechanism 3 is formed by, for example, a G coupling which clamps the protrusions 2 a and 4 a.

A bearing hole 2 b is formed in the bearing housing 2. The bearing hole 2 b penetrates through the turbocharger C in the horizontal direction. A bearing 7 is provided in the bearing hole 2 b. A shaft 8 is pivotally supported by the bearing 7 in a freely rotatable manner. At a left end portion of the shaft 8, a turbine impeller 9 is assembled. The turbine impeller 9 is accommodated in the turbine housing 4 in a freely rotatable manner. Furthermore, a compressor impeller 10 is assembled to a right end portion of the shaft 8. The compressor impeller 10 is accommodated in the compressor housing 6 in a freely rotatable manner.

An intake port 11 is formed in the compressor housing 6. The intake port 11 opens to the right side of the turbocharger C. The intake port 11 is connected to an air cleaner (not illustrated). Furthermore, in a state where the bearing housing 2 and the compressor housing 6 are connected by the fastening bolt 5, a diffuser flow passage 12 is formed. The diffuser flow passage 12 is formed by opposing surfaces of the bearing housing 2 and the compressor housing 6. The diffuser flow passage 12 pressurizes the air. The diffuser flow passage 12 is annularly formed outward from an inner side in the radial direction of the shaft 8. The diffuser flow passage 12 communicates with the intake port 11 via the compressor impeller 10 on the inner side in the above radial direction.

Furthermore, the compressor housing 6 includes a compressor scroll flow passage 13. The compressor scroll flow passage 13 is annular. The compressor scroll flow passage 13 is positioned on an outer side in the radial direction of the shaft 8 with respect to the diffuser flow passage 12. The compressor scroll flow passage 13 communicates with an intake port of the engine (not illustrated). The compressor scroll flow passage 13 also communicates with the diffuser flow passage 12. When the compressor impeller 10 rotates, therefore, the air is sucked into the compressor housing 6 from the intake port 11. The sucked air is accelerated by the action of the centrifugal force in the process of flowing through blades of the compressor impeller 10. The accelerated air is pressurized by the diffuser flow passage 12 and the compressor scroll flow passage 13. The pressurized air is guided to the intake port of the engine.

A discharge port 14 is formed in the turbine housing 4. The discharge port 14 opens to the left side of the turbocharger C. The discharge port 14 is connected to an exhaust gas purification device (not illustrated). In the turbine housing 4, a flow passage 15 and a turbine scroll flow passage 16 are provided. The turbine scroll flow passage 16 is annular. The turbine scroll flow passage 16 is positioned on an outer side in the radial direction of the turbine impeller 9 with respect to the flow passage 15. The turbine scroll flow passage 16 communicates with a gas inlet port (not illustrated). Exhaust gas discharged from an exhaust manifold of the engine (not illustrated) is guided to the gas inlet port. The turbine scroll flow passage 16 also communicates with the turbine impeller 9 via the flow passage 15 described above. Therefore, the exhaust gas guided from the gas inlet port to the turbine scroll flow passage 16 is guided to the discharge port 14 via the flow passage 15 and the turbine impeller 9. The exhaust gas guided to the discharge port 14 rotates the turbine impeller 9 in the process of flowing therethrough.

Then, the turning force of the turbine impeller 9 is transmitted to the compressor impeller 10 via the shaft 8. As described above, the air is pressurized by the turning force of the compressor impeller 10 and guided to the intake port of the engine.

FIG. 2 is a view extracted from a one-dot chain line part of FIG. 1. As illustrated in FIG. 2, an oil passage 2 c is formed in the bearing housing 2. The oil passage 2 c penetrates from the outside of the bearing housing 2 to the bearing hole 2 b. Lubricating oil flows into the bearing hole 2 b from the oil passage 2 c. A bearing 7 is disposed in the bearing hole 2 b. An insertion hole 7 b is formed in the main body portion 7 a of the bearing 7. The insertion hole 7 b penetrates in the axial direction of the shaft 8 (hereinafter simply referred to as the axial direction). The shaft 8 is inserted through the insertion hole 7 b. On an inner circumferential surface 7 c of the insertion hole 7 b, two bearing surfaces 7 d and 7 e are formed. The bearing surfaces 7 d and 7 e are spaced apart in the axial direction.

Of the main body portion 7 a, an end surface (thrust bearing surface 7 i which will be described later) on the turbine impeller 9 side (left side in FIG. 2) protrudes from the bearing hole 2 b to the turbine impeller 9 side. A space s for scattering the lubricating oil is formed radially outward from the thrust bearing surface 7 i. The space s communicates with an oil discharge port 2 f side vertically below the main body portion 7 a and vertically below the bearing 7. Here, in the space s, an oil passage (not illustrated) may communicate vertically above the main body portion 7 a. In this case, lubricating oil is guided from the oil passage (not illustrated) to the space s.

A part of the bearing surface 7 d protrudes from the bearing hole 2 b toward the turbine impeller 9. A part of the bearing surface 7 d is positioned in the space s (on an inner side in the radial direction of the space s). In the case where an entirety of the main body portion 7 a is accommodated in the bearing hole 2 b, the heat dissipation property in the vicinity of the bearing surface 7 d of the main body portion 7 a is deteriorated since the main body portion 7 a is covered by the bearing housing 2. A part of the bearing surface 7 d is positioned in the space s (on the inner side in the radial direction of the space s), whereby the heat dissipation property of the main body portion 7 a in the vicinity of the bearing surface 7 d is improved. Furthermore, for example, in the case where an oil passage that bifurcates from the oil passage 2 c and guides the lubricating oil directly to the space s is provided, the main body portion 7 a is cooled by the lubricating oil, and thus the cooling performance of the bearing surface 7 d is improved. Here, the case where a part of the bearing surface 7 d on the turbine impeller 9 side protrudes from the bearing hole 2 b has been described. However, the bearing surface 7 e on the compressor impeller 10 side may protrude from the bearing hole 2 b (toward the compressor impeller 10).

A part of the lubricating oil supplied to the bearing hole 2 b passes through an oil hole 7 g and flows into the inner circumferential surface 7 c of the main body portion 7 a. The oil hole 7 g penetrates through the main body portion 7 a from the inner circumferential surface 7 c to the outer circumferential surface 7 f. The lubricating oil flowed in spreads horizontally in FIG. 2 from the oil hole 7 g. The spread lubricating oil is supplied to clearances between the shaft 8 and each of the bearing surfaces 7 d and 7 e. The shaft 8 is pivotally supported by the oil film pressure of the lubricating oil supplied to the clearance between the shaft 8 and each of the bearing surfaces 7 d and 7 e.

A through hole 7 h is further provided in the main body portion 7 a. The through hole 7 h penetrates from the inner circumferential surface 7 c to the outer circumferential surface 7 f. A pin hole 2 d is formed in the bearing housing 2. The pin hole 2 d is formed at a portion facing the through hole 7 h. The pin hole 2 d penetrates through a wall portion forming the bearing hole 2 b. A positioning pin 20 is fitted to the pin hole 2 d from the lower side in FIG. 2. The tip of the positioning pin 20 is inserted into the through hole 7 h of the bearing 7. The positioning pin 20 regulates rotation and movement in the axial direction of the bearing 7.

An oil thrower member 21 is attached to the shaft 8. The oil thrower member 21 is arranged on the right side (the compressor impeller 10 side) in FIG. 2 with respect to the main body portion 7 a. The oil thrower member 21 is an annular member. The oil thrower member 21 scatters the lubricating oil flowing to the compressor impeller 10 side along the shaft 8 to the outer side in the radial direction. That is, leakage of lubricating oil to the compressor impeller 10 side is suppressed by the oil thrower member 21.

The oil thrower member 21 is axially facing the main body portion 7 a. Of the oil thrower member 21, an outer diameter of an opposing surface 21 a (bearing-receiving surface) facing the main body portion 7 a is larger than an inner diameter of the bearing surface 7 e. The outer diameter is also larger than the outer diameter of the main body portion 7 a.

The shaft 8 has a large diameter portion 8 a. The large diameter portion 8 a has an outer diameter larger than an inner diameter of the bearing surface 7 d of the main body portion 7 a. The outer diameter of the large diameter portion 8 a is also larger than the outer diameter of the main body portion 7 a. The large diameter portion 8 a is positioned on the left side (the turbine impeller 9 side) in FIG. 2 with respect to the main body portion 7 a. The large diameter portion 8 a axially faces the main body portion 7 a.

In this manner, movement of the main body portion 7 a in the axial direction is restricted by the positioning pin 20. The main body portion 7 a is interposed between the oil thrower member 21 and the large diameter portion 8 a in the axial direction. Lubricating oil is supplied to a clearance between the main body portion 7 a and the oil thrower member 21 and to a clearance between the main body portion 7 a and the large diameter portion 8 a. When the shaft 8 moves in the axial direction, the oil thrower member 21 or the large diameter portion 8 a is supported by the oil film pressure with respect to the main body portion 7 a. That is, in the bearing 7, both end surfaces in the axial direction of the main body portion 7 a form thrust bearing surfaces 7 i and 7 j. The thrust bearing surfaces 7 i and 7 j receive a thrust load.

Furthermore, damper portions 7 k and 7 m are formed on each of both axial end sides of the outer circumferential surface of the main body portion 7 a. The damper portions 7 k and 7 m suppress vibration of the shaft 8 by the oil film pressure of the lubricating oil supplied to the clearance with an inner circumferential surface 2 e of the bearing hole 2 b.

As illustrated in FIG. 1, in the bearing housing 2, an oil discharge port 2 f is formed vertically below the bearing 7. The lubricating oil used for lubrication and suppression of vibration of the bearing 7 is discharged from the oil discharge port 2 f.

FIG. 3 is a view of a broken line part extracted from FIG. 1. As illustrated in FIG. 3, an accommodation hole 2 g is formed in the bearing housing 2. The accommodation hole 2 g is adjacent to a back surface 10 a of the compressor impeller 10. One end of the bearing hole 2 b opens on a bottom surface portion 2 h of the accommodation hole 2 g. The thrust bearing surface 7 j formed at one end of the bearing 7 protrudes from the bottom surface portion 2 h toward the compressor impeller 10.

The shaft 8 has a medium diameter portion 8 b. The medium diameter portion 8 b is a portion pivotally supported by the bearing surface 7 e of the bearing 7. Furthermore, a small diameter portion 8 c is formed on the compressor impeller 10 side of the shaft 8 with respect to the medium diameter portion 8 b. Between the medium diameter portion 8 b and the small diameter portion 8 c, a step surface 8 d is provided. The step surface 8 d extends in the radial direction. The step surface 8 d connects the medium diameter portion 8 b and the small diameter portion 8 c.

The oil thrower member 21 has a large protrusion 21 b. The large protrusion 21 b is annular. In the large protrusion 21 b, an opposing surface 21 a facing the thrust bearing surface 7 j is formed. The large protrusion 21 b protrudes radially outward from a main body portion 21 c of the oil thrower member 21. The large protrusion 21 b extends radially outward from the damper portion 7 m of the bearing 7.

A small protrusion 21 d is provided to the main body portion 21 c on the compressor impeller 10 side with the large protrusion 21 b. The small protrusion 21 d has a smaller diameter than the large protrusion 21 b. In the small protrusion 21 d, an inclined surface 21 e is formed. The inclined surface 21 e has a smaller diameter toward the compressor impeller 10. For example, two ring grooves 21 g are provided side by side on a tip portion 21 f on the compressor impeller 10 side with respect to the small protrusion 21 d. The ring grooves 21 g are annular. A seal ring (not illustrated) is provided in a ring groove 21 g.

The small diameter portion 8 c of the shaft 8 is inserted through the oil thrower member 21. The large protrusion 21 b (opposing surface 21 a) of the oil thrower member 21 abuts against the step surface 8 d of the shaft 8. The compressor impeller 10, through which the shaft 8 is inserted, abuts against the tip portion 21 f of the oil thrower member 21. The oil thrower member 21 and the compressor impeller 10 are held by the axial force generated between a fastening member 22 (see FIG. 1) and the step surface 8 d. When the shaft 8 rotates, the oil thrower member 21 and the compressor impeller 10 rotate together with the shaft 8.

In this manner, the oil thrower member 21 is provided to the shaft 8. The opposing surface 21 a of the oil thrower member 21 faces the thrust bearing surface 7 j. Here, the case where the bearing-receiving surface (opposing surface 21 a) facing the thrust bearing surface 7 j is provided separately from the shaft 8 has been described. However, like the large diameter portion 8 a, the bearing-receiving surface to face the thrust bearing surface 7 j may be formed in the shaft 8.

A seal partition member 23 is disposed radially outside the oil thrower member 21. The seal partition member 23 is, for example, press-fitted into the accommodation hole 2 g of the bearing housing 2. The seal partition member 23 is attached to the bearing housing 2. Here, for example, the axial length of a part of the seal partition member 23 that is press-fitted into the accommodation hole 2 g may not extend to an inner surface 25 c of a seal plate portion 25, which will be described later. As illustrated in FIG. 3, the seal partition member 23 may be press-fitted only to a partial region of the accommodation hole 2 g (seal partition member 23) on the compressor impeller 10 side. That is, of an outer circumferential surface of the seal partition member 23, the inner surface 25 c (bearing 7) side is slightly recessed radially inward. Of the outer circumferential surface of the seal partition member 23, the inner surface 25 c (bearing 7) side is spaced apart (has a clearance) from the accommodation hole 2 g of the bearing housing 2. In this case, reducing the press-fitted area of the seal partition member 23 allows press-fitting work to be performed stably.

FIG. 4A is a perspective view of the seal partition member 23. FIG. 4 (b) is a perspective view of the seal partition member 23 when viewed from a direction different from that in FIG. 4A. As illustrated in FIGS. 3, 4A, and 4B, the seal partition member 23 has a partition wall portion 24, a seal plate portion 25, and a middle portion 26. The middle portion 26 is positioned between the partition wall portion 24 and the seal plate portion 25. The partition wall portion 24, the seal plate portion 25, and the middle portion 26 are integrally formed.

The partition wall portion 24 has a large diameter hole 24 a. The large protrusion 21 b of the oil thrower member 21 is inserted through the large diameter hole 24 a. An inner circumferential surface 24 b of the large diameter hole 24 a faces the large protrusion 21 b in the radial direction. The opposing surface 21 a of the large protrusion 21 b is positioned closer to the bearing 7 than the large diameter hole 24 a is. Furthermore, of the large protrusions 21 b, an opposite surface 21 h on the small protrusion 21 d side is positioned inside the large diameter hole 24 a. That is, the inner circumferential surface 24 b of the large diameter hole 24 a is positioned radially outside the opposite surface 21 h of the large protrusion 21 b.

In the partition wall portion 24, an inclined surface 24 c is formed on the bearing 7 side. The inclined surface 24 c is positioned radially outside the large diameter hole 24 a. For example, the inclined surface 24 c extends at least vertically above the thrust bearing surface 7 j. A flat surface portion 24 d is provided between the large diameter hole 24 a and the inclined surface 24 c. The flat surface portion 24 d extends in the radial direction.

The inclined surface 24 c is inclined in such a direction as to extend radially outward toward the bearing 7. That is, the inclined surface 24 c is inclined with respect to the direction perpendicular to the axial direction (radial direction of the shaft 8). The inclined surface 24 c is positioned radially outside the thrust bearing surface 7 j. The inclined surface 24 c faces the thrust bearing surface 7 j in the radial direction.

Here, of the inclined surface 24 c, an imaginary extension line La in contact with an outer diameter end portion 24 e on the lower side (vertically lower side) in FIG. 3 is indicated by a two-dot chain line. As illustrated in FIG. 1, the oil discharge port 2 f is positioned on this extension line La.

An outer diameter wall portion 24 f is provided on an outer side in the radial direction of the inclined surface 24 c. The outer diameter wall portion 24 f abuts against the bottom surface portion 2 h. That is, the outer diameter wall portion 24 f extends radially outward from the inclined surface 24 c. The outer diameter wall portion 24 f extends in the radial direction of the shaft 8. A groove 2 i is formed in the bottom surface portion 2 h of the accommodation hole 2 g of the bearing housing 2. The groove 2 i faces the inclined surface 24 c of the partition wall portion 24 in the axial direction. The groove 2 i is positioned radially outside the bearing hole 2 b. The groove 2 i extends in the circumferential direction of the bearing hole 2 b. The axial position (depth) of the groove 2 i is, for example, within the range in which the bearing surface 7 e extends in the axial direction. Of the groove 2 i, an inner wall surface 2 ja on the outer side in the radial direction abuts against an outer circumferential end 24 g of the inclined surface 24 c.

The groove 2 i is positioned radially outside the large diameter hole 24 a. The large protrusion 21 b of the oil thrower member 21 inserted through the large diameter hole 24 a is positioned on an inner side than the groove 2 i in the radial direction. That is, in the radial direction, a part of the large protrusion 21 b on an outer side faces the bottom surface portion 2 h which is positioned on an inner side in the radial direction than the groove 2 i in the axial direction.

As illustrated in FIGS. 4A and 4B, a first cutout portion 24 h is formed at a vertically lower side of the outer diameter wall portion 24 f. The first cutout portion 24 h is positioned vertically lower than the center of the large diameter hole 24 a (center of the shaft 8). On the outer diameter wall portion 24 f, two tapered surfaces 24 i and 24 j are formed. The two tapered surfaces 24 i and 24 j are formed at cutout portions where the first cutout portion 24 h is formed. That is, both end portions of the first cutout portion 24 h in the circumferential direction are formed by the two tapered surfaces 24 i and 24 j. The tapered surfaces 24 i and 24 j extend approximately in the radial direction of the shaft 8. The tapered surfaces 24 i and 24 j are approximately line-symmetrical with each other as an example. Furthermore, end portions of the tapered surfaces 24 i and 24 j on an outer side in the radial direction extend vertically lower than the large diameter hole 24 a. In other words, as an example, end portions of the tapered surfaces 24 i and 24 j on an inner side in the radial direction is positioned vertically lower than the center of the large diameter hole 24 a. With the inner side end portion as a starting point, each of the tapered surfaces 24 i and 24 j extends lower than the large diameter hole 24 a in the radial direction.

Referring back to FIG. 3, the seal plate portion 25 is disposed while spaced apart from the partition wall portion 24 on an opposite side of the bearing 7. A main body portion 25 a of the seal plate portion 25 is annular. Of the main body portion 25 a, an outer surface 25 b facing the back surface 10 a of the compressor impeller 10 is recessed toward the bearing 7 more on an inner side in the radial direction. The inner surface 25 c of the main body portion 25 a facing the partition wall portion 24 includes a region protruding toward the partition wall portion 24 toward the radially inner side on the inner diameter side. An annular protrusion 25 d is formed on an end portion of the inner surface 25 c on the inner side in the radial direction. The annular protrusion 25 d protrudes from the inner surface 25 c toward the partition wall portion 24.

A plate hole 25 e is formed at the center of the annular protrusion 25 d. The plate hole 25 e penetrates up to the back surface 10 a. The tip portion 21 f of the oil thrower member 21 is inserted in the plate hole 25 e. The small protrusion 21 d extends from the annular protrusion 25 d toward the partition wall portion 24. An enlarged diameter portion 25 g is formed at an end portion 25 f of the plate hole 25 e on the partition wall portion 24 side. The enlarged diameter portion 25 g has a larger inner diameter toward the partition wall portion 24 (the side opposite to the compressor impeller 10, the large protrusion 21 b side). The inclined surface 21 e of the oil thrower member 21 is facing an inner side in the radial direction of the enlarged diameter portion 25 g.

As illustrated in FIGS. 4A and 4B, the middle portion 26 is positioned between the partition wall portion 24 and the seal plate portion 25 in the axial direction. The middle portion 26 is continuous to an outer circumferential surface of each of the partition wall portion 24 and the seal plate portion 25. Moreover, the middle portion 26 extends in the circumferential direction of the large diameter hole 24 a. Like the partition wall portion 24, a second cutout portion 26 a is formed in the middle portion 26 at a vertically lower side. The second cutout portion 26 a is positioned vertically lower than the center of the large diameter hole 24 a (center of the shaft 8). In the middle portion 26, two tapered surfaces 26 b and 26 c are formed at cutout portions where the second cutout portion 26 a is formed. The tapered surfaces 26 b and 26 c extend in the radial direction of the shaft 8. That is, both end portions of the second cutout portion 26 a in the circumferential direction are formed by the two tapered surfaces 26 b and 26 c. The tapered surfaces 26 b and 26 c are approximately line symmetric with each other as an example. Furthermore, end portions of the tapered surfaces 26 b and 26 c on an outer side in the radial direction extend vertically lower than the large diameter hole 24 a. In other words, as an example, end portions of the tapered surfaces 26 b and 26 c on an inner side in the radial direction is positioned vertically lower than the center of the large diameter hole 24 a. With the inner side end portion as a starting point, each of the tapered surfaces 26 b and 26 c extends vertically lower than the large diameter hole 24 a in the radial direction

The second cutout portion 26 a is continuous with the first cutout portion 24 h in the axial direction. In other words, the tapered surfaces 24 i and 24 j and the tapered surfaces 26 b and 26 c are continuous in the axial direction and are flush with each other as an example.

FIG. 5 is a partially extracted view of the bearing housing 2. Note that, in FIG. 5, a perspective view of the bearing housing 2 cut at the same position as that in FIG. 1 when viewed from the right front side in FIG. 1 is illustrated.

As illustrated in FIG. 5, in the bearing housing 2, a communication passage 2 k communicating the accommodation hole 2 g and the oil discharge port 2 f is formed. A third cutout portion 2 m is further formed in the bottom surface portion 2 h of the accommodation hole 2 g. The third cutout portion 2 m is positioned vertically lower than the center of the bearing hole 2 b (center of the shaft 8).

FIG. 6A is a view of the bearing housing 2 when viewed from the right side in FIG. 5. FIG. 6B is a perspective view of a broken line part of FIG. 6A when viewed from below. As illustrated in FIGS. 6A and 6B, two tapered surfaces 2 n and 2 p are formed on the bottom surface portion 2 h. The tapered surfaces 2 n and 2 p are formed at cutout portions where the third cutout portion 2 m is formed. That is, both end portions of the third cutout portion 2 m in the circumferential direction are formed by the two tapered surfaces 2 n and 2 p. The tapered surfaces 2 n and 2 p extend approximately in the radial direction of the shaft 8. The tapered surfaces 2 n and 2 p are approximately line symmetric with each other as an example. Furthermore, end portions of the tapered surfaces 2 n and 2 p on an outer side in the radial direction extend vertically lower than the large diameter hole 24 a. In other words, as an example, end portions of the tapered surfaces 2 n and 2 p on an inner side in the radial direction is positioned vertically lower than the center of the large diameter hole 24 a. With the inner side end portion as a starting point, each of the tapered surfaces 2 n and 2 p extends vertically lower than the large diameter hole 24 a in the radial direction.

When the seal partition member 23 is disposed in the accommodation hole 2 g of the bearing housing 2, the third cutout portion 2 m may be continuous with the first cutout portion 24 h in the axial direction. In other words, each pair of the tapered surfaces 24 i and 2 p and the tapered surfaces 24 j and 2 n may be continuous in the axial direction and be flush with each other. The present disclosure is not limited to this, and alternatively the third cutout portion 2 m may extend vertically lower than the first cutout portion 24 h. That is, the bottom surface portion 2 h of the accommodation hole 2 g extends vertically lower than the outer diameter wall portion 24 f. And a step surface extending in the radial direction is formed at a connecting portion between the bottom surface portion 2 h and the outer diameter wall portion 24 f. In this case, this step surface enables preventing lubricating oil from entering the oil supply side (oil passage 2 c side) in the axial direction.

Referring back to FIG. 3, a space S of the bearing housing 2 is formed by the accommodation hole 2 g and the groove 2 i illustrated in FIG. 3. The partition wall portion 24 divides the space S into two spaces Sa and Sb in the axial direction. The space Sa on the bearing 7 side is adjacent to the inclined surface 24 c. Furthermore, the space Sb on the compressor impeller 10 side is formed inside the seal partition member 23 (that is, a space surrounded by the partition wall portion 24, the seal plate portion 25, and the middle portion 26). These spaces Sa and Sb communicate with the communication passage 2 k via the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m.

The lubricating oil having lubricated the thrust bearing surface 7 j scatters radially outward from the opposing surface 21 a by the centrifugal force. Then, the lubricating oil flows toward the bearing 7 while flowing radially outward along the inclined surface 24 c of the partition wall portion 24. The lubricating oil scattered vertically downward directly passes through the communication passage 2 k and is discharged from the oil discharge port 2 f. The lubricating oil scattered vertically upward flows into the groove 2 i and is guided to the communication passage 2 k along the groove 2 i. The lubricating oil guided to the communication passage 2 k is discharged from the oil discharge port 2 f.

Furthermore, a part of the lubricating oil passes through a clearance between the large protrusion 21 b of the oil thrower member 21 and the large diameter hole 24 a of the partition wall portion 24 and flows out into the space Sb. The lubricating oil flowed out into the space Sb is scattered radially outward by the centrifugal force. The lubricating oil scattered vertically downward passes through the communication passage 2 k and is discharged from the oil discharge port 2 f. The lubricating oil scattered vertically upward is guided to the communication passage 2 k along the inner wall surface of the middle portion 26 in the circumferential direction. The lubricating oil guided to the communication passage 2 k is discharged from the oil discharge port 2 f.

It is assumed that a part of the lubricating oil has entered the clearance between the inclined surface 21 e of the oil thrower member 21 and the enlarged diameter portion 25 g of the seal plate portion 25. In this case, due to the centrifugal force accompanying the rotation of the oil thrower member 21, the lubricating oil flows radially outward, whereby a force to pull back toward the bearing 7 is generated in the lubricating oil. Then, the lubricating oil scatters radially outward from a portion of the small protrusion 21 d protruding slightly from the annular protrusion 25 d toward the bearing 7. The scattered lubricating oil is discharged from the oil discharge port 2 f via the communication passage 2 k.

As described above, in the present embodiment, the inclined surface 24 c is provided radially outside the thrust bearing surface 7 j. Therefore, the lubricating oil having lubricated the thrust bearing surface 7 j flows in the axial direction along the inclined surface 24 c. As a result, the scattered lubricating oil hardly interferes with the flow of lubricating oil to be scattered subsequently. The lubricating oil is efficiently discharged from the space Sa to the communication passage 2 k. This enables improving the oil draining property.

Further, as described above, it is assumed that the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m are provided. In this case, the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p suppress winding up of the lubricating oil from the communication passage 2 k. In other words, it is possible to reduce intrusion of lubricating oil toward the center of the shaft 8. Here, it is sufficient to provide any one of the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m; however, the present disclosure is not limited thereto. For example, a plurality of cutout portions may be provided such as including any combination of two out of the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m or including all the three. In this case, it is possible to synergistically suppress winding up of the lubricating oil from the communication passage 2 k.

Of the small protrusions 21 d, a surface on the large protrusion 21 b side may be positioned closer to the large protrusion 21 b (to the bearing 7) than the end surface of the annular protrusion 25 d on the large protrusion 21 b side. In this case, as described above, the lubricating oil is easily scattered radially outward from a portion of the small protrusion 21 d protruding slightly from the annular protrusion 25 d toward the bearing V. Inflow of the lubricating oil toward the ring groove 21 g (seal ring not illustrated) is suppressed.

An inner wall surface 2 ka is a part of the bearing housing 2. The inner wall surface 2 ka forms the communication passage 2 k. The inner wall surface 2 ka is continuous from, for example, a communicating portion between the communication passage 2 k and the accommodation hole 2 g. The inner wall surface 2 ka may be positioned on the compressor impeller 10 side (right side in FIG. 3) of the communication passage 2 k. A plate surface 25 ca is formed on the inner surface 25 c of the seal plate portion 25 on an outer side in the radial direction. The plate surface 25 ca may be positioned on the second cutout portion 26 a side of the middle portion 26. The inner wall surface 2 ka is positioned closer to the large protrusion 21 b (to the bearing 7) than the plate surface 25 ca is. In this case, a space Sb is widely secured. This enables improving the oil draining property.

Furthermore, the axial position of the opposing surface 21 a of the oil thrower member 21 may be arranged between the axial position of the bottom surface portion 2 h of the accommodation hole 2 g and that of the flat surface portion 24 d of the partition wall portion 24. In this case, lubricating oil scattered from the opposing surface 21 a is guided to the inclined surface 24 c. This enables improving the oil draining property.

The axial position of the opposite surface 21 h of the oil thrower member 21 may be arranged between the axial position of the flat surface portion 24 d of the partition wall portion 24 and that of the surface of the partition wall portion 24 opposite to the flat surface portion 24 d (surface facing the annular protrusion 25 d). In this case, an orifice is formed between the oil thrower member 21 and the partition wall portion 24. At an outlet side of the orifice, formation of mist is suppressed.

Moreover, the inner diameter of the intersection between an extension line extending radially outward from the opposing surface 21 a and the inclined surface 24 c may be less than an average value of the inner diameter of the inner wall surface 2 ja of the groove 2 i on an outer side in the radial direction (distance from the central of the shaft 8) and the inner diameter of the inner wall surface 2 jb of the groove 2 i on an outer side in the radial direction. In this case, the scattered lubricating oil is easily guided to the inclined surface 24 c even at a low rotation speed. Even at a low rotation speed, the inclined surface 24 c and the groove 2 i effectively function.

In addition, as illustrated in FIG. 1, the groove 2 i may be positioned right above the oil discharge port 2 f. In this case, lubricating oil guided to the groove 2 i can be discharged directly to the oil discharge port 2 f directly below.

The radial position of the outer circumferential surface of the large protrusion 21 b may be arranged between the radial position of the damper portion 7 m of the bearing 7 and that of the inner wall surface 2 jb of the groove 2 i on an outer side in the radial direction. In this case, lubricating oil flowing out in the axial direction from the bearing 7 side tends to collides with the large protrusion 21 b. Therefore, the lubricating oil is easily guided to the groove 2 i.

It is preferable to design the clearance between the inner diameter of the large diameter hole 24 a and the outer diameter of the large protrusion 21 b to be small. In the case where the partition wall portion 24 is integrated, as a part of the seal partition member 23, with the seal plate portion 25 and the middle portion 26, for example, by press-fitting the seal partition member 23 into the accommodation hole 2 g, after installation, it becomes easier to reduce a dimensional difference between the inner diameter of the large diameter hole 24 a and the outer diameter of the large protrusion 21 b after attachment. As a result, it is further suppressed that the lubricating oil diffuses (for example, formed into mist) and flows out from the clearance (the aforementioned orifice) between the large protrusion 21 b and the large diameter hole 24 a into the space Sb.

FIG. 7 is an explanatory view for explaining a modification and illustrates a cross-sectional view of the modification at a position corresponding to that of FIG. 3. In FIG. 7, the illustration of the compressor impeller 10 is omitted. In the embodiment described above, the case where the seal partition member 23 integrally in which the partition wall portion 24, the seal plate portion 25, and the middle portion 26 are integrally formed is provided has been described. As illustrated in FIG. 7, in the modification, a partition wall portion 124 is formed separately from a seal plate portion 125 and a middle portion 126.

A screw hole 2 q is provided in the bottom surface portion 2 h of the bearing housing 2. The screw hole 2 q is provided radially outside a groove 2 i. The partition wall portion 124 includes a through hole 124 k. The through hole 124 k faces the screw hole 2 q. The through hole 124 k penetrates in the axial direction. A fastening member 127 is inserted into the through hole 124 k. A screw portion 127 a is formed at the tip portion of the fastening member 127. The screw portion 127 a is screwed into the screw hole 2 q. In this manner, the partition wall portion 124 is assembled to the bearing housing 2. The seal plate portion 125 is press-fitted into an accommodation hole 2 g and thereby assembled to the bearing housing 2. Here, the case where the partition wall portion 124 is assembled to the bearing housing 2 by the fastening member 127 and the seal plate portion 125 is press-fitted into the accommodation hole 2 g has been described. However, for example, the partition wall portion 124 may be assembled to the bearing housing 2 by press fitting, and the seal plate portion 125 may be assembled to the bearing housing 2 by a bolt or the like.

An opposite surface 124 m is a surface of the partition wall portion 124 that faces the seal plate portion 125. On the opposite surface 124 m, a protruding portion 124 n is formed. The protruding portion 124 n is positioned on an outer side in the radial direction of the opposite surface 124 m. The protruding portion 124 n protrudes toward the seal plate portion 125. A middle portion 126 protrudes from an outer circumferential side of an inner surface 125 c of the seal plate portion 125 toward the partition wall portion 124. A front end surface 126 c of the middle portion 126 extends in the radial direction of the shaft 8. The front end surface 126 c abuts against the protruding portion 124 n of the partition wall portion 124.

As in the modification, the partition wall portion 124 may be formed separately from the seal plate portion 125 and the middle portion 126. Also in this case, like in the embodiment described above, the lubricating oil having lubricated the thrust bearing surface 7 j flows in the axial direction along an inclined surface 24 c. Therefore, the lubricating oil flowing in the axial direction hardly interferes with the flow of the lubricating oil to be scattered subsequently. As a result, the lubricating oil is efficiently discharged from a space Sa to a communication passage 2 k. This enables improving the oil draining property.

Although the embodiments have been described with reference to the accompanying drawings, it is naturally understood that the present disclosure is not limited to the above embodiments. It is clear that those skilled in the art can conceive various modifications or variations within the scope described in the claims, and it is understood that they are naturally also within the technical scope.

For example, in the modification described above, the case where the middle portion 126 is integrally formed with the seal plate portion 125 has been described. However, the middle portion may be integrally formed with the partition wall portion and be formed separately from the seal plate portion. Regardless of whether the middle portion is formed as an integrated body or a separated body, the partition wall portion requires 5-axis machining or the like for example. The degradation of workability caused by integrally forming the middle portion and the partition wall portion is suppressed. On the other hand, in the case where the middle portion is formed as a separate body, the seal plate portion does not require complex processing such as 5-axis machining. This enables improving the manufacturability. Furthermore, in assembling work of the seal plate portion, management of the position in the rotational direction of the shaft 8 becomes unnecessary. Workability is improved. However, when the middle portion 126 is integrally formed with the seal plate portion 125, it is sufficient to attach only the partition wall portion 124 to the bearing housing 2 by the fastening member 127. Therefore, for example, the middle portion may be integrally formed with the partition wall portion. In this case, the length of the fastening member 127 can be reduced by the length of the middle portion 126 as compared with the case where the fastening member penetrates through the middle portion and the partition wall portion and is screwed into the screw hole of the bearing housing 2.

Furthermore, for example, in the case where the partition wall portion 24 and the seal plate portion 25 are integrally formed as in the embodiment described above, the seal partition member 23 (the partition wall portion 24 and the seal plate portion 25) can be formed by, for example, casting or the like. Therefore, complicated machining such as 5-axis machining becomes unnecessary. This enables improving the manufacturability. In addition, the partition wall portion 24 and the seal plate portion 25 can be assembled into the accommodation hole 2 g together. Workability is improved. Furthermore, with the partition wall portion 24 abutting against the bottom surface portion 2 h, the entire position of the seal partition member 23 is determined. Stability of assembly is improved. Furthermore, it is sufficient to assemble the seal plate portion 25 to the bearing housing 2 without directly assembling the partition wall portion 24 to the bearing housing 2. The through hole 124 k or the screw hole 2 q become unnecessary. Therefore, it is possible to improve the oil draining property by expanding the groove 2 i radially outward, for example, to the same position as that of an inner circumferential surface of the middle portion 26. Furthermore, for example, another cutout portion may be provided in the middle portion 26 on the side opposite to the first cutout portion 24 h (for example, on an upper side in the vertical direction) as long as the strength of the middle portion 26 can be maintained on the minimum level. In other words, it is only required to prevent winding up of the lubricating oil by the tapered surfaces 24 i and 24 j of the first cutout portion 24 h. Since a portion vertically above the tapered surfaces 24 i and 24 j is for maintaining the strength of the middle portion 26, a cutout portion may be provided. In this case, it is possible to reduce the weight and material cost. It is possible to secure the space Sb to be wide and to improve the oil draining property.

Furthermore, in the modification described above, the case where the protruding portion 124 n is formed on the opposite surface 124 m of the partition wall portion 124 has been described. However, the protruding portion 124 n may not be formed on the opposite surface 124 m.

Furthermore, in the embodiment and the modification described above, the case where the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m are provided has been described. However, the first cutout portion 24 h, the second cutout portion 26 a, and the third cutout portion 2 m may not be provided.

Furthermore, in the embodiment and the modification described above, the case where each pair of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p are arranged approximately line-symmetrically with each other has been described. However, each pair of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p may be provided at least in only a region positioned from vertically below the shaft 8 to the forward side in the rotation direction. For example, in the case where the shaft 8 is rotating in a clockwise direction when viewed from the compressor impeller 10, provided is a cutout portion extending in the circumferential direction from vertically below to the tapered surfaces (24 i, 26 b, and 2 p) positioned on the left side in FIG. 4B. However, in the case where each pair of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p is arranged approximately line-symmetrically with each other, this can be commonly applied also to a turbocharger including a shaft 8 that rotates in the opposite direction. In this case, it is possible to omit provision of two members depending on a rotation direction of the shaft 8.

Furthermore, in the embodiment and the modification described above, the case where the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p extend in the radial direction of the shaft 8 has been described. However, the present disclosure is not limited to this. Inclination angles of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p can be set desirably. Furthermore, for example, inclination angles of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p may vary in the radial direction. The tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p may be curved.

Furthermore, in the embodiment and the modification described above, the case where the end portions of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p on an outer side in the radial direction extend vertically lower than the large diameter hole 24 a has been described. However, the positions of the lower ends of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p in the radial direction may be the same as that of the large diameter hole 24 a. However, the positions of the lower ends of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p in the radial direction may be vertically upper than that of the large diameter hole 24 a. However, in the case where the end portions of the tapered surfaces 24 i and 24 j, the tapered surfaces 26 b and 26 c, and the tapered surfaces 2 n and 2 p on an outer side in the radial direction extend vertically lower than the large diameter hole 24 a, winding up of the lubricating oil from the communication passage 2 k can be efficiently suppressed. Similarly, end portions of the tapered surfaces on an inner side in the radial direction (starting point side) is not limited to be positioned vertically lower than the center of the large diameter hole 24 a. For example, the end portions on the inner side in the radial direction may be positioned at the same position in the vertical direction as that of the large diameter hole 24 a as long as the thickness of a wall surface with the large diameter hole 24 a or the bearing hole 2 b can be ensured in terms of strength. The end portions of the tapered surfaces on an inner side in the radial direction (starting point side) may be positioned vertically upper than the large diameter hole 24 a.

Furthermore, in the embodiment and the modification described above, the case where the opposing surface 21 a of the large protrusion 21 b is positioned closer to the bearing 7 than the large diameter hole 24 a is has been described. The shaft 8 or the oil thrower member 21 move in the axial direction with respect to the bearing housing 2 by a thrust load (axial force) generated during operation. For example, assuming that a thrust load is generated in a direction in which the shaft 8 or the oil thrower member 21 moves toward the compressor impeller 10. In this case, the large diameter portion 8 a of the shaft 8 moves to a position where the large diameter portion 8 a approximately abuts against the bearing 7. Assuming that a thrust load is generated in a direction in which the shaft 8 or the oil thrower member 21 moves toward the turbine impeller 9. In this case, the opposing surface 21 a of the oil thrower member 21 moves to a position where the opposing surface 21 a approximately abuts against the bearing 7. Here, the opposing surface 21 a of the large protrusion 21 b may be positioned closer to the bearing 7 side than the large diameter hole 24 a is even when the shaft 8 or the oil thrower member 21 move toward the compressor impeller 10. In this case, the inclined surface 24 c is arranged so as to be always positioned radially outside the thrust bearing surface 7 j. In this manner, regardless of the direction in which the thrust load acts on the shaft 8, it is possible to stably improve the oil draining property.

Furthermore, in the embodiment and the modification described above, the case where the inner circumferential surface 24 b of the large diameter hole 24 a is positioned on an outer side in the radial direction of the opposite surface 21 h of the large protrusion 21 b has been described. However, the inner circumferential surface 24 b of the large diameter hole 24 a may not be positioned radially outside the opposite surface 21 h of the large protrusion 21 b. For example, the opposite surface 21 h of the large protrusion 21 b may be positioned closer to the seal plate portion 25 or 125 than the inner circumferential surface 24 b of the large diameter hole 24 a is. Furthermore, the opposite surface 21 h of the large protrusion 21 b may be positioned radially inward from an end portion of the inner circumferential surface 24 b of the large diameter hole 24 a on the seal plate portion 25 or 125 side. Note that in the case where the inner circumferential surface 24 b of the large diameter hole 24 a is positioned radially outside the opposite surface 21 h of the large protrusion 21 b, the following effects are obtained. That is, it is suppressed that the lubricating oil diffuses (for example, formed into mist) and flows out from the clearance (the aforementioned orifice) between the large protrusion 21 b and the large diameter hole 24 a into the space Sb. This enables improving the oil draining property. Moreover, the inner circumferential surface 24 b of the large diameter hole 24 a may be arranged so as to be always positioned on an outer side in the radial direction of the opposite surface 21 h of the large protrusion 21 b even when the shaft 8 or the oil thrower member 21 moves in the axial direction toward the compressor impeller 10 during operation. In this case, regardless of the direction in which the thrust load acts on the shaft 8, it is possible to stably improve the oil draining property.

Furthermore, in the embodiment and the modification described above, the case where the small protrusion 21 d extends closer to the partition wall portion 24 or 124 than the annular protrusion 25 d is has been described. However, the small protrusion 21 d may extend to the same position as that of the annular protrusion 25 d toward the partition wall portion 24 or 124. The annular protrusion 25 d may extend closer to the partition wall portion 24 or 124 than the small protrusion 21 d is. In the case where the small protrusion 21 d extends closer to the partition wall portion 24 or 124 than the annular protrusion 25 d is, the lubricating oil is easily scattered radially outward by the centrifugal force from the small protrusion 21 d. This enables improving the oil draining property. Furthermore, the small protrusions 21 d may be arranged so as to always extend closer to the partition wall portion 24 or 124 than the annular protrusion 25 d is even when the shaft 8 or the oil thrower member 21 moves in the axial direction toward the compressor impeller 10 during operation. In this case, regardless of the direction in which the thrust load acts on the shaft 8, it is possible to stably improve the oil draining property.

Furthermore, in the embodiment and the modification described above, the case where the groove 2 i is formed in the bottom surface portion 2 h has been described. However, the groove 2 i may not be provided in the bottom surface portion 2 h. In the case where the groove 2 i is formed in the bottom surface portion 2 h, the lubricating oil flowed toward the bearing 7 along the inclined surface 24 c is efficiently guided to the communication passage 2 k. For example, even in the case where a space that can be formed with respect to the bearing 7 on an inner side in the radial direction of the inclined surface 24 c is limited, the oil draining property can be improved.

Furthermore, in the embodiment and the modification described above, the case where the oil discharge port 2 f is positioned on the imaginary extension line La in contact with the outer diameter end portion 24 e of the inclined surface 24 c positioned vertically lower than the shaft 8 have been described. However, the oil discharge port 2 f may be at a position deviated from the imaginary extension line La of the inclined surface 24 c. In the case where the oil discharge port 2 f is positioned on the imaginary extension line La of the inclined surface 24 c, a part of the lubricating oil is directly guided from the outer diameter end portion 24 e to the oil discharge port 2 f. This enables improving the oil draining property.

Furthermore, in the embodiment and the modification described above, the case where a cross-sectional shape of the inclined surface 24 c illustrated in FIG. 3 is linear has been described. However, in the cross-section illustrated in FIG. 3, the inclined surface is not limited to be linear and may be curved, for example. Even in this case, as long as the oil discharge port 2 f is positioned on an imaginary extension line in contact with the outer diameter end portion of the inclined surface, a part of the lubricating oil is directly guided from the outer diameter end portion to the oil discharge port 2 f. This enables improving the oil draining property.

Furthermore, in the embodiment and the modification described above, the case where the partition wall portions 24 and 124, the seal plate portions 25 and 125, and the middle portions 26 and 126 are arranged on the compressor impeller 10 side with respect to the bearing 7 has been described. However, the partition wall portions 24 and 124, the seal plate portions 25 and 125, and the middle portions 26 and 126 may be arranged on the turbine impeller 9 side with respect to the bearing 7.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied to a turbocharger including a bearing having a thrust bearing surface. 

What is claimed is:
 1. A turbocharger comprising: a housing; a bearing disposed in the housing and having a thrust bearing surface; a partition wall portion assembled to the housing, the partition wall portion including an inclined surface positioned on an outer side in a radial direction of the thrust bearing surface, extending at least vertically above the thrust bearing surface, and inclined with respect to a direction perpendicular to an axial direction of a shaft; and a groove formed in the housing and facing the inclined surface in the axial direction of the shaft.
 2. The turbocharger according to claim 1, wherein the inclined surface is inclined in such a direction as to extend radially outward toward the bearing.
 3. The turbocharger according to claim 1, further comprising an oil discharge port formed in the housing and positioned on an imaginary extension line in contact with an outer diameter end portion of the inclined surface positioned vertically below the shaft.
 4. The turbocharger according to claim 2, further comprising an oil discharge port formed in the housing and positioned on an imaginary extension line in contact with an outer diameter end portion of the inclined surface positioned vertically below the shaft.
 5. The turbocharger according to claim 1, further comprising: an outer diameter wall portion extending outward in the radial direction from the inclined surface in the partition wall portion; and a first cutout portion formed on a vertically lower side lower than a center of the shaft in the outer diameter wall portion.
 6. The turbocharger according to claim 2, further comprising: an outer diameter wall portion extending outward in the radial direction from the inclined surface in the partition wall portion; and a first cutout portion formed on a vertically lower side lower than a center of the shaft in the outer diameter wall portion.
 7. The turbocharger according to claim 3, further comprising: an outer diameter wall portion extending outward in the radial direction from the inclined surface in the partition wall portion; and a first cutout portion formed on a vertically lower side lower than a center of the shaft in the outer diameter wall portion.
 8. The turbocharger according to claim 4, further comprising: an outer diameter wall portion extending outward in the radial direction from the inclined surface in the partition wall portion; and a first cutout portion formed on a vertically lower side lower than a center of the shaft in the outer diameter wall portion.
 9. The turbocharger according to claim 1, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 10. The turbocharger according to claim 2, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 11. The turbocharger according to claim 3, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 12. The turbocharger according to claim 4, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 13. The turbocharger according to claim 5, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 14. The turbocharger according to claim 6, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 15. The turbocharger according to claim 7, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 16. The turbocharger according to claim 8, further comprising a seal plate portion spaced apart from the partition wall portion on an opposite side of the bearing.
 17. The turbocharger according to claim 9, wherein the partition wall portion and the seal plate portion are integrally formed.
 18. The turbocharger according to claim 9, further comprising: a middle portion provided between the partition wall portion and the seal plate portion; and a second cutout portion formed in the middle portion in a vertically lower side lower than a center of the shaft.
 19. The turbocharger according to claim 17, further comprising: a middle portion provided between the partition wall portion and the seal plate portion; and a second cutout portion formed in the middle portion in a vertically lower side lower than a center of the shaft. 